Evaluation of novel cathepsin-X inhibitors in vitro and in vivo and their ability to improve cathepsin-B-directed antitumor therapy

New therapeutic targets that could improve current antitumor therapy and overcome cancer resistance are urgently needed. Promising candidates are lysosomal cysteine cathepsins, proteolytical enzymes involved in various critical steps during cancer progression. Among them, cathepsin X, which acts solely as a carboxypeptidase, has received much attention. Our results indicate that the triazole-based selective reversible inhibitor of cathepsin X named Z9 (1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-((4-isopropyl-4H-1,2,4-triazol-3-yl)thio)ethan-1-one) significantly reduces tumor progression, both in vitro in cell-based functional assays and in vivo in two independent tumor mouse models: the FVB/PyMT transgenic and MMTV-PyMT orthotopic breast cancer mouse models. One of the mechanisms by which cathepsin X contributes to cancer progression is the compensation of cathepsin-B activity loss. Our results confirm that cathepsin-B inhibition is compensated by an increase in cathepsin X activity and protein levels. Furthermore, the simultaneous inhibition of both cathepsins B and X with potent, selective, reversible inhibitors exerted a synergistic effect in impairing processes of tumor progression in in vitro cell-based assays of tumor cell migration and spheroid growth. Taken together, our data demonstrate that Z9 impairs tumor progression both in vitro and in vivo and can be used in combination with other peptidase inhibitors as an innovative approach to overcome resistance to antipeptidase therapy.

A Tumor Microenvironment-Responsive Co/ZIF-8/ICG/Pt Nanoplatform for Chemodynamic and Enhanced Photodynamic Antitumor Therapy

Hypoxia and overexpression of hydrogen peroxide (H2O2) in tumor microenvironment (TME) are conducive to cancer cells proliferation, which greatly hinder cancer treatment. Here, we design a novel TME-responsive therapeutic nanoplatform...

Secondary acquired nasolacrimal duct obstruction due to the toxic effect of antineoplastic agents

In recent years, the use of chemotherapeutic agents in the treatment of cancer became more common. At the same time, the number of complications associated with this is also increasing. Among the rare complications of therapy with some antitumor drugs is the formation of secondary acquired nasolacrimal duct obstruction. The aim was to analyze and systematize information about secondary acquired nasolacrimal duct obstruction due to the toxic effect of antitumor drugs. Materials and methods. The authors analyzed the literature available in the MEDLINE and RSCI search engines in February 2021. The analysis included 55 publications. Results. In the literature, there are indications that such antitumor drugs as 5-fluorouracil and similar drugs, mitomycin C, as well as therapy with radioactive iodine, are characterized by the possibility of developing complications in the form of secondary acquired nasolacrimal duct obstruction. Preliminary screening of the drainage function of the tear ducts, as well as prescribing of local anti-inflammatory and antibacterial treatment in the form of instillations in the conjunctival sac can help to reduce the risk of complications. This explains the need to recommend patients to consult an ophthalmologist if there are relevant complaints before or during treatment. In the absence of timely treatment, obstruction of the tear ducts often becomes an indication for reconstructive interventions. Conclusion. Secondary acquired nasolacrimal duct obstruction is one of the rare, but systematically occurring complications of antitumor therapy. To date, the pathogenesis of these complications is not fully understood, and some of the data is contradictory. In the future, the accumulation of knowledge concerning the pathogenesis of this complication will contribute to the development of personalized methods of prevention.

Changes in Glycanic Determinants of Lymphocytes Membranes in Peripheral Blood in Patients with B-Cell Chronic Lymphocytic Leukemia under Antitumor Therapy

The purpose of the study was to study the nature of changes in the exposure of surface glycans of peripheral blood lymphocytes in patients with B-cell chronic lymphocytic leukemia under conditions of antitumor therapy. Materials and methods. We studied the features of exposure of surface glycotopes of peripheral blood lymphocytes in patients with B-cell chronic lymphocytic leukemia under conditions of antitumor therapy using a set of seven lectins labeled with FITC and monoclonal antibodies to Tn-antigen- FITC for the detection of Tn antigen and CD43 exposure on blood lymphocytes. Cytostatic therapy included cyclophosphamide, vincristine (oncovin), prednisolone. Data were recorded on a Beckman Coulter EPICS flow cytometer. The results were processed using FCS3 Express. Results and discussion. The number of lymphocytes of healthy donors with a positive reaction to ConA, PHA-L, SNA, MAA-II and α1-acid glycoprotein amounted to 16.0±3.0%, 23.0±2.3%, 15.0±1.5%, 25.0±1.8% and 15.0±1.3%, respectively. The number of LABA-, UEA I-positive lymphocytes was 0.90±0.03% and 2.9±0.2%, respectively, and there was no binding to antibodies to Tn- and CD43-antigens. In the blood of patients with chronic lymphocytic leukemia, the level of ConA-, SNA- and MAA-II-positive lymphocytes increased relative to control by 2.2, 3.7 and 2.6 times, respectively. The number of LABA- and UEA I-positive lymphocytes in patients with chronic lymphocytic leukemia increased by 11 (p <0.01) and 23 (p <0.001) times and amounted to 10.5±0.5% and 67.5±5.5% respectively. The number of lymphocytes with CD43 antigen on their surface increased by 72 times, and the Tn antigen increased by 80 times. Cytostatic therapy reduced the level of LABA- and UEA I-positive lymphocytes by almost half, and MAA II-positive cells and lymphocytes interacting with antibodies to CD43 and Tn antigen by a third. The level of PHA-L-positive lymphocytes in the blood of chronic lymphocytic leukemia patients after undergoing alkylating therapy increased by 18.0±2.0% and almost did not differ from those obtained in the control group. Conclusion. 1. In chronic lymphocytic leukemia patients, the structure of glycoconjugates in peripheral blood lymphocytes changes, manifested in increased exposure of L-fucose, α-mannose and N-acetylneuraminic acid, which is confirmed by a significant increase in relation to the control of the number of ConA-, SNA-, MAA-II-, LABA I-positive cells. 2. Patients with chronic lymphocytic leukemia showed a significant increase in the number of lymphocytes, in which the markers of carcinogenesis CD43 and Tn antigens were found. 3. Cytostatic therapy significantly reduced the level of LABA-, UEA I- and MAA II-positive cells, as well as partially Tn- and CD43-antigen-positive lymphocytes, which indicates its positive effect on the treatment of chronic lymphocytic leukemia

Adjunctive Probiotic Lactobacillus rhamnosus Probio-M9 Administration Enhances the Effect of Anti-PD-1 Antitumor Therapy via Restoring Antibiotic-Disrupted Gut Microbiota

Emerging evidence supports that the efficacy of immune checkpoint blockade (ICB) therapy is associated with the host’s gut microbiota, as prior antibiotic intake often leads to poor outcome and low responsiveness toward ICB treatment. Therefore, we hypothesized that the efficacy of ICB therapy like anti-programmed cell death protein-1 (PD-1) treatment required an intact host gut microbiota, and it was established that probiotics could enhance the recovery of gut microbiota disruption by external stimuli. Thus, the present study aimed to evaluate the effect of the probiotics, Lactobacillus rhamnosus Probio-M9, on recovering antibiotic-disrupted gut microbiota and its impact on the outcome of ICB therapy in tumor-bearing mice. We first disrupted the mouse microbiota by antibiotics and then remediated the gut microbiota by probiotics or naturally. Tumor transplantation was then performed, followed by anti-PD-1-based antitumor therapy. Changes in the fecal metagenomes and the tumor suppression effect were monitored during different stages of the experiment. Our results showed that Probio-M9 synergized with ICB therapy, significantly improving tumor inhibition compared with groups not receiving the probiotic treatment (P &lt; 0.05 at most time points). The synergistic effect was accompanied by effective restoration of antibiotic-disrupted fecal microbiome that was characterized by a drastically reduced Shannon diversity value and shifted composition of dominating taxa. Moreover, probiotic administration significantly increased the relative abundance of beneficial bacteria (e.g., Bifidobacterium pseudolongum, Parabacteroides distasonis, and some Bacteroides species; 0.0001 &lt; P &lt; 0.05). The gut microbiome changes were accompanied by mild reshaping of the functional metagenomes characterized by enrichment in sugar degradation and vitamin and amino acid synthesis pathways. Collectively, this study supported that probiotic administration could enhance the efficacy and responsiveness of anti-PD-1-based immunotherapy, and Probio-M9 could be a potential candidate of microbe-based synergistic tumor therapeutics. The preclinical data obtained here would support the design of future human clinical trials for further consolidating the current findings and for safety assessment of probiotic adjunctive treatment in ICB therapy.

In Situ-Forming Cellulose/Albumin-Based Injectable Hydrogels for Localized Antitumor Therapy

Injectable hydrogels, which are formed in situ by changing the external stimuli, have the unique characteristics of easy handling and minimal invasiveness, thus providing the advantage of bypass surgical operation and improving patient compliance. Using external temperature stimuli to realize the sol-to-gel transition when preparing injectable hydrogel is essential since the temperature is stable in vivo and controllable during ex vivo, although the hydrogels obtained possibly have low mechanical strength and stability. In this work, we designed an in situ fast-forming injectable cellulose/albumin-based hydrogel (HPC-g-AA/BSA hydrogels) that responded to body temperature and which was a well-stabilized hydrogen-bonding network, effectively solving the problem of poor mechanical properties. The application of localized delivery of chemotherapeutic drugs of HPC-g-AA/BSA hydrogels was evaluated. In vitro and in vivo results show that HPC-g-AA/BSA hydrogels exhibited higher antitumor efficacy of reducing tumor size and seem ideal for localized antitumor therapy.

Biological Adaptations of Tumor Cells to Radiation Therapy

Radiation therapy has been used worldwide for many decades as a therapeutic regimen for the treatment of different types of cancer. Just over 50% of cancer patients are treated with radiotherapy alone or with other types of antitumor therapy. Radiation can induce different types of cell damage: directly, it can induce DNA single- and double-strand breaks; indirectly, it can induce the formation of free radicals, which can interact with different components of cells, including the genome, promoting structural alterations. During treatment, radiosensitive tumor cells decrease their rate of cell proliferation through cell cycle arrest stimulated by DNA damage. Then, DNA repair mechanisms are turned on to alleviate the damage, but cell death mechanisms are activated if damage persists and cannot be repaired. Interestingly, some cells can evade apoptosis because genome damage triggers the cellular overactivation of some DNA repair pathways. Additionally, some surviving cells exposed to radiation may have alterations in the expression of tumor suppressor genes and oncogenes, enhancing different hallmarks of cancer, such as migration, invasion, and metastasis. The activation of these genetic pathways and other epigenetic and structural cellular changes in the irradiated cells and extracellular factors, such as the tumor microenvironment, is crucial in developing tumor radioresistance. The tumor microenvironment is largely responsible for the poor efficacy of antitumor therapy, tumor relapse, and poor prognosis observed in some patients. In this review, we describe strategies that tumor cells use to respond to radiation stress, adapt, and proliferate after radiotherapy, promoting the appearance of tumor radioresistance. Also, we discuss the clinical impact of radioresistance in patient outcomes. Knowledge of such cellular strategies could help the development of new clinical interventions, increasing the radiosensitization of tumor cells, improving the effectiveness of these therapies, and increasing the survival of patients.